CN109070209B - Active metal powder in-flight heat treatment process - Google Patents

Abstract

A reactive metal powder in-flight heat treatment process is provided. For example, such a process includes providing active metal powder; and contacting the active metal powder with at least one additive gas while performing the in-flight heat treatment process, thereby obtaining a pristine active metal powder.

Description

Active metal powder in-flight heat treatment process

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to US Provisional Application No. 62/320,874, filed April 11, 2016. This document is incorporated by reference in its entirety.

technical field

The present disclosure relates to the field of production of spherical powders such as reactive metal powders. More particularly, the present disclosure relates to methods and apparatus for producing reactive metal powders by having improved flow properties.

Background technique

In general, the desired characteristics of high quality active metal powders will be a combination of high sphericity, density, purity, flowability and a small amount of gas entrapment pores. Fine powders can be used in applications such as 3D printing, powder jet molding, hot isostatic pressing and coating. This fine powder is used in aerospace, biomedical and industrial applications.

Powders with poor flow properties may tend to form aggregates with lower density and higher surface area. These aggregates can be detrimental when used in applications requiring fine reactive metal powders. In addition, active powders with poor flow properties can cause pipe blockages and/or stick to the walls of the atomizing chamber of the atomizing device or to the walls of the delivery pipe. Furthermore, powders in aggregate form are more difficult to sieve when separating powders into different size distributions. Manipulating powders in aggregate form also increases safety risks because higher surface area translates into higher reactivity.

On the contrary, metal powders with improved flow properties are desired for various reasons. For example, they can be more easily used in powder metallurgy processes as additive manufacturing and coatings.

SUMMARY OF THE INVENTION

Accordingly, it would be highly desirable to provide an apparatus, system or method that addresses, at least in part, the poor flow properties of reactive metal powders associated with electrostatic sensitivity. High-flow powders generally convert at higher apparent densities and can diffuse more easily to produce a uniform powder layer.

According to one aspect, the present invention provides an in-flight heat treatment process for active metal powder, comprising:

provide reactive metal powders; and

During the in-flight heat treatment process, the active metal powder is contacted with at least one additive gas.

According to another aspect, the present invention provides an in-flight heat treatment process for active metal powder, comprising:

provide reactive metal powders; and

During the in-flight heat treatment process, the active metal powder is contacted with at least one additive gas, thereby obtaining a pristine active metal powder, the pristine active metal powder comprising:

A particle size distribution of about 10 to about 53 μm having a flow of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 10 to about 45 μm having a flowability of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 15 to about 45 μm with a flow of less than 40 seconds as measured in accordance with ASTM B213;

A particle size distribution of about 15 to about 53 μm having a flow of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 25 to about 45 μm having a flowability of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 25 to about 53 μm having a flow of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 45 to about 75 μm having a flow of less than 28 seconds as measured according to ASTM B213;

A particle size distribution of about 45 to about 106 μm with a flow of less than 28 seconds as measured according to ASTM B213;

A particle size distribution of from about 45 to about 150 μm, measured in accordance with ASTM B213, having a flowability of less than 28 seconds; and/or

Particle size distribution of about 45 to about 180 μm with less than 28 seconds flow as measured according to ASTM B213.

According to another aspect, the present invention provides an in-flight heat treatment process for active metal powder, comprising:

provide reactive metal powders; and

During the in-flight heat treatment process, the active metal powder is contacted with at least one additive gas, thereby obtaining a pristine active metal powder, the pristine active metal powder comprising:

A particle size distribution of about 10 to about 53 μm having a flowability of less than 30 seconds as measured in accordance with ASTM B213;

A particle size distribution of about 10 to about 45 μm having a flowability of less than 30 seconds as measured in accordance with ASTM B213;

A particle size distribution of about 15 to about 45 μm with a flow of less than 30 seconds as measured according to ASTM B213;

A particle size distribution of about 15 to about 53 μm with flowability of less than 30 seconds as measured in accordance with ASTM B213;

A particle size distribution of from about 25 to about 45 μm, measured in accordance with ASTM B213, having a flowability of less than 30 seconds; and/or

Particle size distribution of about 25 to about 53 μm with flowability of less than 30 seconds as measured according to ASTM B213.

According to another aspect, the present invention provides an in-flight heat treatment process for active metal powder, comprising:

Provide active metal powder;

mixing together an in-flight thermal treatment process gas and at least one additive gas to obtain an in-flight thermal treatment process gas mixture;

During the in-flight heat treatment process, the active metal powder is brought into contact with the mixture.

According to another aspect, the present invention provides an in-flight heat treatment process for active metal powder, comprising:

Provide active metal powder;

mixing together an in-flight thermal treatment process gas and at least one additive gas to obtain an in-flight thermal treatment process gas mixture;

During the in-flight heat treatment process, the active metal powder is brought into contact with the mixture, thereby obtaining a pristine active metal powder, the pristine active metal powder comprising:

A particle size distribution of about 10 to about 53 μm having a flow of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 10 to about 45 μm having a flowability of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 15 to about 45 μm with a flow of less than 40 seconds as measured in accordance with ASTM B213;

A particle size distribution of about 15 to about 53 μm having a flow of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 25 to about 45 μm having a flowability of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 25 to about 53 μm having a flow of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 45 to about 75 μm having a flow of less than 28 seconds as measured according to ASTM B213;

A particle size distribution of about 45 to about 106 μm with a flow of less than 28 seconds as measured according to ASTM B213;

A particle size distribution of from about 45 to about 150 μm, measured in accordance with ASTM B213, having a flowability of less than 28 seconds; and/or

Particle size distribution of about 45 to about 180 μm with less than 28 seconds flow as measured according to ASTM B213.

According to another aspect, the present invention provides an in-flight heat treatment process for active metal powder, comprising:

Provide active metal powder;

mixing together an in-flight thermal treatment process gas and at least one additive gas to obtain an in-flight thermal treatment process gas mixture;

During the in-flight heat treatment process, the active metal powder is brought into contact with the mixture, thereby obtaining a pristine active metal powder, the pristine active metal powder comprising:

A particle size distribution of about 10 to about 53 μm having a flowability of less than 30 seconds as measured in accordance with ASTM B213;

A particle size distribution of about 10 to about 45 μm having a flowability of less than 30 seconds as measured in accordance with ASTM B213;

A particle size distribution of about 15 to about 45 μm with a flow of less than 30 seconds as measured according to ASTM B213;

A particle size distribution of about 15 to about 53 μm with flowability of less than 30 seconds as measured in accordance with ASTM B213;

A particle size distribution of from about 25 to about 45 μm, measured in accordance with ASTM B213, having a flowability of less than 30 seconds; and/or

Particle size distribution of about 25 to about 53 μm with flowability of less than 30 seconds as measured according to ASTM B213.

According to another aspect, the present invention provides an in-flight heat treatment process for active metal powder, comprising:

provide reactive metal powders; and

The active metal powder is contacted with at least one additive gas while performing the in-flight heat treatment process under conditions sufficient to produce a pristine active metal powder having less than 1000 ppm of each from the additive gas The added content of electronegative atoms and/or molecules.

According to another aspect, the present invention provides an in-flight heat treatment process for active metal powder, comprising:

Provide active metal powder;

mixing together an in-flight thermal treatment process gas and at least one additive gas to obtain an in-flight thermal treatment process gas mixture;

The active metal powder source is contacted with the in-flight heat treatment process gas mixture while conducting the in-flight heat treatment process under conditions sufficient to produce pristine active metal powder having less than 1000 ppm from additive gas The added content of electronegative atoms and/or molecules.

According to another aspect, the present invention provides an in-flight heat treatment process for active metal powder, comprising:

Provide active metal powder;

mixing together an in-flight thermal treatment process gas and at least one additive gas to obtain an in-flight thermal treatment process gas mixture;

During the in-flight heat treatment process, contacting the active metal powder with the in-flight heat treatment process gas mixture to obtain pristine metal powder;

optionally sieving the virgin reactive metal powder to obtain a powder having a predetermined particle size; and

The powder having the predetermined particle size is optionally contacted with water.

The present disclosure relates to methods, processes, systems and apparatus capable of producing reactive metal powders that exhibit high flow properties. This effect can be observed for various particle size distributions, including fine particle size distributions, which would not even flow in a Hall flowmeter without the treatment. One advantage of the current method is that no foreign particles are added to the powder. It simply results in an improved finish.

The various techniques described in this disclosure were observed to help reduce the electrostatic sensitivity of powders, which resulted in improved powder flow.

Description of drawings

The following figures represent non-limiting examples, in which:

Figure 1 is a cross-sectional view of an in-flight heat treatment process using a plasma torch and axial powder injection;

Figure 2 is a cross-sectional view of an in-flight heat treatment process using a plasma torch and radial powder injection;

3 is a cross-sectional view of an in-flight thermal treatment process using a plasma torch, radial powder injection, and downstream additive gas injection;

Figure 4 is a cross-sectional view of an in-flight heat treatment process using a gas heater combined with a furnace and axial powder injection;

5 is a cross-sectional view of an exemplary atomization system;

6 is a schematic diagram of reactive metal powder particles formed according to an atomization process, wherein the heated metal source is not in contact with the additive gas;

7 is a schematic diagram of reactive metal powder particles formed according to an atomization process, wherein a heated metal source is contacted with an additive gas;

8 shows a schematic diagram of a particle having radius R and a plurality of particles each having radius r formed from the same mass of material;

Figure 9 shows TOF-SIMS characteristics of particles obtained from various tests;

Figure 10 is a photograph of a batch of metal powder formed according to an atomization process that does not include a step of contacting an additive gas; and

Figure 11 is a photograph of a batch of metal powders formed according to an atomization process, wherein the metal source has been contacted with the additive gas.

Detailed ways

The following examples are presented in a non-limiting manner.

Unless the content clearly dictates otherwise, when used in conjunction with the term "comprising" in the claims and/or specification, the word "a" or "an" may mean "an", but it is also used in conjunction with "one or more" ", "at least one" and "one or more than one" have the same meaning. Similarly, unless the content clearly dictates otherwise, the word "another" may mean at least a second or more.

As used in this specification and in the claims, the words "comprising" (and any form of including, such as "comprising" and "comprising"), "having" (and any form of having, such as "having" and "having" "), "includes" (and any form of including, such as "includes" and "includes"), or "contains" (and any form of containment, such as "contains" and "comprising"), is inclusive or open-ended does not exclude other unrecited elements or process steps.

The expression "atomization zone" as used herein when referring to a method, apparatus or system for producing a metal powder refers to the area in which the material is atomized into droplets of the material. Those skilled in the art will understand that the size of the atomization zone will vary depending on various parameters, such as the temperature of the atomization device, the speed of the atomization device, the material in the atomization device, the power of the atomization device, the entry into the atomization zone The temperature of the front material, the properties of the material, the size of the material, the resistivity of the material, etc.

The expression "heated zone of the atomizer" as used herein refers to the region of the powder that is hot enough to react with the electronegative atoms of the additive gas to create a depletion layer, as discussed in this disclosure.

The expression "metal powder has an X-Y μm particle size distribution” means that it has less than 5% by weight of particles above Y μm size, the latter value being measured according to the ASTM B214 standard. It also means that it has less than 6% by weight of particles below Xμm size (d6≧Xμm), the latter value being measured according to the ASTM B822 standard.

The expression "metal powder having a particle size of 15-45 μm" means that it has less than 5% by weight of particles above 45 μm (measured according to ASTM B214 standard) and less than 6% by weight of particles below 15 μm (measured according to ASTM B822 standard).

The expression "gas to metal ratio" as used herein refers to the ratio of the mass of injected gas per unit time (kg/s) provided in the atomization zone to the mass feed rate of the metal source (kg/s).

The expression "active metal powder" as used herein refers to metal powders that cannot be efficiently prepared by conventional gas atomization processes using tightly coupled nozzles. For example, the active metal powder may be a powder containing at least one selected from the group consisting of titanium, titanium alloys, zirconium, zirconium alloys, magnesium, magnesium alloys, aluminum, and aluminum alloys.

The expression "raw active metal powder" as used herein refers to the active metal powder obtained directly from the atomization process without any post-processing steps, such as sieving or classification techniques.

The expression "in-flight heat treatment process" as used herein refers to a process that effectively modifies the chemical composition of the metal particle surface of the metal powder and improves the fluidity of the metal powder. For example, this in-flight heat treatment process may be an atomization process, a spheroidization process, an in-flight furnace heating process or an in-flight plasma heating process.

Active metal powders with fine particle size (eg, within the size distribution below 106 μm) were observed to have larger surface areas and stronger surface interactions. These result in poorer flow behavior than coarse powders. The flowability of powders depends on one or more of various factors, such as particle shape, particle size distribution, surface smoothness, moisture level, satellite content, and the presence of static electricity. Therefore, the flowability of powders is a complex macroscopic feature created by the balance between adhesion and gravity on powder particles.

For example, the particle size distribution can be:

A particle size distribution of about 10 to about 53 μm having a flow of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 10 to about 45 μm having a flowability of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 15 to about 45 μm with a flow of less than 40 seconds as measured in accordance with ASTM B213;

A particle size distribution of about 15 to about 53 μm having a flow of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 25 to about 45 μm having a flowability of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 25 to about 53 μm having a flow of less than 40 seconds as measured according to ASTM B213;

A particle size distribution of about 45 to about 75 μm having a flow of less than 28 seconds as measured according to ASTM B213;

A particle size distribution of about 45 to about 106 μm with a flow of less than 28 seconds as measured according to ASTM B213;

A particle size distribution of from about 45 to about 150 μm, measured in accordance with ASTM B213, having a flowability of less than 28 seconds; and/or

Particle size distribution of about 45 to about 180 μm with less than 28 seconds flow as measured according to ASTM B213.

For example, the particle size distribution can be a particle size distribution of about 10 to about 53 μm with a flowability of less than 36 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution may be a particle size distribution of about 10 to about 53 μm with a flowability of less than 32 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution can be a particle size distribution of about 10 to about 53 μm with a flowability of less than 30 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution may be a particle size distribution of about 10 to about 53 μm with a flow of less than 28 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution can be a particle size distribution of about 10 to about 45 μm with a flowability of less than 36 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution can be a particle size distribution of about 10 to about 45 μm having a flowability of less than 32 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution can be a particle size distribution of about 10 to about 45 μm with a flowability of less than 30 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution can be a particle size distribution of about 10 to about 45 μm with a flowability of less than 28 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution may be a particle size distribution of about 15 to about 45 μm having a flowability of less than 36 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution can be a particle size distribution of about 15 to about 45 μm with a flowability of less than 32 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution can be a particle size distribution of about 15 to about 45 μm with a flowability of less than 30 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution can be a particle size distribution of about 15 to about 45 μm with a flow of less than 28 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution can be a particle size distribution of about 15 to about 53 μm with a flow of less than 36 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution can be a particle size distribution of about 15 to about 53 μm with a flowability of less than 32 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution can be a particle size distribution of about 15 to about 53 μm with a flowability of less than 30 seconds as measured in accordance with ASTM B213.

For example, the particle size distribution can be a particle size distribution of about 15 to about 53 μm with a flow of less than 28 seconds as measured in accordance with ASTM B213.

For example, the virgin reactive metal powder comprises a particle size distribution of about 25 to about 45 μm with a flow of less than 36 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powders comprise virgin reactive metal powders comprising a particle size distribution of about 25 to about 45 μm having a flowability of less than 32 seconds as measured in accordance with ASTM B213.

For example, the virgin reactive metal powders comprise virgin reactive metal powders comprising a particle size distribution of about 25 to about 45 μm having a flowability of less than 30 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder comprises a particle size distribution of about 25 to about 45 μm with flowability of less than 25 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder contains a particle size distribution of about 25 to about 53 μm with a flowability of less than 36 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder contains a particle size distribution of about 25 to about 53 μm with a flowability of less than 32 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder contains a particle size distribution of from about 25 to about 53 μm, measured according to ASTM B213, with a flowability of less than 30 seconds.

For example, the virgin reactive metal powder contains a particle size distribution of about 25 to about 53 μm with flowability of less than 25 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder comprises a particle size distribution of about 45 to about 75 μm with a flow of less than 26 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder comprises a particle size distribution of about 45 to about 75 μm with flowability of less than 25 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder contains a particle size distribution of about 45 to about 75 μm with a flowability of less than 24 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder contains a particle size distribution of about 45 to about 75 μm with a flow of less than 23 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder comprises a particle size distribution of about 45 to about 106 μm with flowability of less than 26 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder comprises a particle size distribution of about 45 to about 106 μm with flowability of less than 25 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder contains a particle size distribution of from about 45 to about 106 μm, measured according to ASTM B213, with a flowability of less than 24 seconds.

For example, the virgin reactive metal powder contains a particle size distribution of about 45 to about 106 μm with flowability of less than 23 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder comprises a particle size distribution of about 45 to about 150 μm with a flow of less than 26 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder contains a particle size distribution of from about 45 to about 150 μm, measured according to ASTM B213, with a flowability of less than 25 seconds.

For example, the virgin reactive metal powder contains a particle size distribution of about 45 to about 150 μm with flowability of less than 24 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder comprises a particle size distribution of about 45 to about 150 μm with a flow of less than 23 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder contains a particle size distribution of from about 45 to about 180 μm, measured according to ASTM B213, with a flowability of less than 26 seconds.

For example, the virgin reactive metal powder comprises a particle size distribution of about 45 to about 180 μm with flowability of less than 25 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder contains a particle size distribution of about 45 to about 180 μm with flowability of less than 24 seconds as measured according to ASTM B213.

For example, the virgin reactive metal powder comprises a particle size distribution of about 45 to about 180 μm with a flow of less than 23 seconds as measured according to ASTM B213.

Those skilled in the art will appreciate that, for example, if 50 g of powder is subjected to a flowability treatment (ie, an on-the-fly heat treatment process as described in this disclosure) to achieve an apparent density of 2.50 g/ ^cm3 (as Ti-6Al-4V) and at Testing ASTM B213 Hall flow at 30 seconds, due to the different bulk densities of these materials, a powder with a similarly treated apparent density (as Al) ^of 1.50 g/cm will flow in 18 seconds and have a similarly treated 3.21 A powder of apparent density (as Zr) of g/ ^cm3 will flow in 39 seconds.

For example, the metal source is contacted with the at least one additive gas in the reaction zone of the reactor.

For example, the metal source is contacted with the at least one additive gas in a hot zone of the reactor.

For example, the metal source is contacted with the at least one additive gas in the atomization zone of the atomizer.

For example, the metal source is contacted with the at least one additive gas in a heated zone of the atomizer.

For example, the metal source is contacted with the at least one additive gas substantially simultaneously with the atomizing gas.

For example, the atomizing gas is an inert gas.

For example, the atomizing gas and additive gas are mixed together prior to contact with the heated metal source.

For example, contact with the additive gas results in the formation of a first layer and a second layer on the surface of the original metal particles, the first layer comprising atoms of the metal and atoms and/or molecules of the additive gas, the first layer One layer is a depletion layer that is deeper and thicker than the native oxide layer, and the second layer is the native oxide layer.

For example, the first layer has a substantially positive charge and the second layer has a substantially negative charge, and wherein the first layer and the second layer have a substantially neutral combined charge.

For example, the process also includes:

The raw active metal powder is sieved to separate the raw active metal powder by particle size distribution.

For example, the process also includes:

After sieving, the separated raw material powders were stirred separately in water.

For example, the water is distilled or demineralized water.

For example, the flowability of the active metal powder is measured on the dry sieved metal powder after it has been stirred.

For example, the active metal powder has an added content of each electronegative atom and/or molecule from the additive gas of less than 1000 ppm.

For example, the active metal powder has an added content of each of said electronegative atoms and/or molecules from the additive gas of less than 500 ppm.

For example, the active metal powder has an added content of each of said electronegative atoms and/or molecules from the additive gas of less than 250 ppm.

For example, the active metal powder has an added content of each of said electronegative atoms and/or molecules from the additive gas of less than 200 ppm.

For example, the active metal powder has an added content of each of said electronegative atoms and/or molecules from the additive gas of less than 150 ppm.

For example, the active metal powder has an added content of each of said electronegative atoms and/or molecules from the additive gas of less than 100 ppm.

For example, the predetermined particle size comprises any particle size distribution of about 10-53 μm, such as 10-45 μm, 15-45 μm, 10-53 μm, 15-53 μm and/or 25-45 μm.

For example, the at least one additive gas is an oxygen-containing gas.

For example, the at least one additive gas is an oxygen-containing gas selected from the group consisting of _O2 , _CO2 , _CO , NO2, air, water vapor, and mixtures thereof.

For example, the at least one additive gas is a halogen-containing gas.

For example, halogen is F, Cl, Br or I.

For example, the at least one additive gas is a hydrogen-containing gas.

For example, the at least one additive gas is a sulfur-containing gas.

For example, the at least one additive gas is a nitrogen-containing gas.

For example, the at least one additive gas is selected from the group consisting of _O2 , _H2O , _CO , _CO2 , NO2, _N2 , _NO3 , _Cl2 , _SO2 , _SO3 , and mixtures thereof.

For example, the active metal powder contains at least one of titanium, zirconium, magnesium, and aluminum.

For example, the active metal powder is a metal powder containing at least one selected from the group consisting of titanium, titanium alloys, zirconium, zirconium alloys, magnesium, magnesium alloys, aluminum, and aluminum alloys.

For example, the active metal powder contains titanium.

For example, active metal powders include titanium alloys.

For example, the active metal powder contains zirconium.

For example, the active metal powder includes a zirconium alloy.

For example, the active metal powder is a metal powder containing at least one member selected from one of titanium and titanium alloys.

For example, the process is carried out by means of at least one plasma torch.

For example, the process is carried out by means of at least one plasma torch.

For example, at least one plasma torch is a radio frequency (RF) plasma torch.

For example, at least one plasma torch is a direct current (DC) plasma torch.

For example, at least one plasma torch is a microwave (MW) plasma torch.

Referring to FIG. 1 , there is shown a cross-section of a flying thermal processing apparatus 10 , which uses a plasma torch 12 to heat powder 18 to be processed and implant axially through an implant probe 14 in the plasma 16 . The heat treatment gas 20 is mixed with the additive gas 22 to carry out a chemical reaction in the reaction zone 24 . The treated powder is then conveyed to powder collector 26 and recovered in collection bucket 32 .

Referring to FIG. 2 , there is shown a cross-section of a flying thermal processing apparatus 10 , which uses a plasma torch 12 to heat powder 18 to be processed and inject it radially through an implant probe 14 in the tail of the plasma 16 . The heat treatment gas 20 is mixed with the additive gas 22 to carry out a chemical reaction in the reaction zone 24 . The treated powder is then conveyed to powder collector 26 and recovered in collection bucket 32 .

Referring to FIG. 3 , there is shown a cross-section of a flying thermal processing apparatus 10 , which uses a plasma torch 12 to heat powder 18 to be processed and inject radially through an implant probe 14 in the tail of the plasma 16 . The heat treatment gases 20 are respectively injected into the additive gases 22 to carry out chemical reactions in the reaction zone 24 . The treated powder is then conveyed to powder collector 26 and recovered in collection bucket 32 .

Referring to FIG. 4 , there is shown a cross-section of the in-flight thermal processing apparatus 10 , which uses a gas heater 28 to heat the powder 18 to be processed and inject axially through the injection probe 14 before entering the furnace 30 . The heat treatment gas 20 is mixed with the additive gas 22 to carry out a chemical reaction in the reaction zone 24 . The treated powder is then conveyed to powder collector 26 and recovered in collection bucket 32 .

Referring now to FIG. 5, an example cross-section of atomization system 102' is shown. The atomization system 102' includes a vessel 118 that receives a feed of a metal source 126 from an upstream system. For example, the feed to metal source 126 is provided as a molten stream, but it may also be provided as a metal rod or wire. The metal source can be heated according to various techniques.

Heated metal source 126 is fed through outlet 124 to atomization zone 132 , which is immediately contacted with atomizing fluid from atomization source 140 . Contacting the heated metal source 126 with the atomizing fluid results in the formation of virgin reactive metal powder 164 which is then expelled from the atomizing zone 132 . For example, the atomizing fluid may be an atomizing gas. For example, the atomizing gas may be an inert gas.

For example, the inert gas may be selected from Ar and/or He.

It should be understood that when atomizing system 102' has atomizing plasma torch 140, the methods and apparatuses described herein for forming reactive metal powders with improved flow properties can be applied to other types of spherical powder production systems, such as Slag shell melting gas atomization process, electrode induction melting gas atomization process (EIGA process), plasma rotating electrode process, plasma (RF, DC, MW) spheroidization process, etc.

According to the illustrated example, the plasma source 140 includes at least one plasma torch. At least one discrete nozzle 148 of at least one plasma torch 140 is centered on the metal source feed. For example, the cross-section of the nozzle 148 may taper toward the metal source feed in order to focus the plasma in contact with the metal source feed. As described elsewhere herein, the nozzles 148 may be positioned such that the apex of the plasma jet contacts the metal source feed from the vessel 118 . Contacting the metal source feed with plasma from at least one plasma source 140 results in atomization of the metal source.

Where multiple plasma torches are provided, the nozzle of the torch is the discrete nozzle 148 of the plasma torch, which is directed from the vessel 118 towards the metal source. For example, the discrete nozzles 148 are positioned such that the apex of the plasma jet output therefrom contacts the metal source from the vessel 118 .

According to various exemplary embodiments of preparing spherical powders, a heated metal source is contacted with at least one additive gas during the atomization process.

The additive gas can be any gas containing electronegative atoms or molecules. The additive gas may include fluorine, chlorine, iodine, bromide, hydrogen-based, nitrogen-based, and carbon-based compounds.

The additive gas may be an oxygen-containing gas. The expression "oxygen-containing gas" as used herein refers to a gas containing at least one oxygen atom. For example, such a gas may be _O2 , _CO2 , _CO , NO2, air, water vapor, ozone, and the like.

According to various exemplary embodiments, the additive gas is contacted with the heated metal source 126 within the atomization zone 132 of the atomizer. The atomization zone 132 is the high heat zone of the atomizer. Thus, the heated metal source 126 is contacted with the atomizing gas and substantially simultaneously with the additive gas within the atomizing zone 132 .

The reaction between the metal particles produced by atomization of the heated metal source and the additive gas can occur as long as the metal particles are hot enough to diffuse electronegative atoms and/or molecules within tens of nanometers in the surface layer.

It should be understood that, in accordance with various exemplary embodiments described herein, in addition to the contact of the heated metal source with the atomizing fluid, the additive gas is contacted with the heated metal source during the atomization process.

It should also be appreciated that some additive gases may be inherently introduced into the atomization fluid, eg, through contamination, potential impurities, or leakage, according to existing atomization processes. For example, the additive gas introduced may include air or oxygen.

However, according to various exemplary embodiments for producing spherical powders described herein, additive gas for contacting the heated metal source is intentionally provided in addition to any additive gas that may be inherently introduced during the atomization process.

According to various exemplary embodiments, a first set of nozzles project atomizing fluid into atomization zone 132 to contact heated metal source 126 and a second set of nozzles inject additive gas into atomization zone 132 to contact the heated metal source 126. Another alternative is that the second set of nozzles may mix the additive gas in the compatible fluid with the atomizing fluid prior to injection into the atomizing zone 132 . For example, the atomizing fluid and additive gas are contacted with the heated metal source 126 at substantially the same time or at a later time. For example, additive gases can be mixed to dilute such additive gases and avoid excessive local concentrations, which could lead to unfavorable or undesired reactions.

According to various alternative exemplary embodiments, the atomizing fluid is an atomizing gas that is mixed with at least one additive gas to form an atomizing mixture. For example, the atomizing gas and additive gas are mixed together prior to contact with the heated metal source. The atomizing gas and additive gas may be mixed together in a gas storage tank or pipe upstream in contact with the heated metal source. For example, additive gas can be injected into the atomizing gas canister. The injected additive gas is in addition to any additive gas inherently present in the atomizing gas.

The amount of additive gas contacted with the heated metal source can be controlled based on the desired final properties of the active metal powder formed by the atomization process.

For example, additive gases contained in the formed reactive metal powder may be considered as contaminants of the metal powder. Thus, the amount of additive gas in contact with the heated metal source is controlled such that the atomic and/or molecular amount of additive gas contained in the active metal powder is kept within certain limits.

For example, chemical composition limits in reactive metal powders can be specified by appropriate standards, such as those in Table 1 AMS 4998, ASTM F3001, ASTM F2924, ASTM B348, ASTM B350, and Table 3 ASTM B550. Accordingly, the amount of additive gas contacted with the heated metal source is controlled based on the composition of the additive gas and one or more limits specified by the standard of one or more atoms and/or molecules that make up the additive gas.

For example, where the additive gas contains oxygen and the active metal powder to be formed is a titanium alloy powder, the amount of additive gas in contact with the heated metal source is controlled such that the amount of oxygen in the active metal powder formed is in accordance with the AMS 4998 standard Below 1800 ppm, below 1300 ppm according to ASTM F3001.

For example, where the additive gas contains carbon and the active metal powder to be formed is a titanium alloy powder, the amount of additive gas in contact with the heated metal source is controlled such that the amount of carbon in the active metal powder formed is in accordance with the AMS 4998 standard Below 1000 ppm and below 800 ppm according to ASTM F3001.

For example, where the additive gas contains hydrogen and the active metal powder to be formed is a titanium alloy powder, the amount of additive gas in contact with the heated metal source is controlled such that the amount of hydrogen in the active metal powder formed is in accordance with AMS 4998 and ASTM F3001 standard is below 120ppm.

For example, in the case where the additive gas contains nitrogen and the active metal powder to be formed is a titanium alloy powder, the amount of additive gas in contact with the heated metal source is controlled such that the amount of nitrogen in the active metal powder formed is in accordance with the AMS 4998 standard Below 400 ppm and below 500 ppm according to ASTM F3001.

For example, where the additive gas contains chlorine and the active metal powder to be formed is titanium metal powder, the amount of additive gas in contact with the heated metal source is controlled such that the amount of chlorine in the active metal powder formed is in accordance with ASTM F3001 standard Below 1000ppm.

For example, the amount of additive gas in contact with the heated metal source can be controlled by controlling the amount of additive gas injected into the atomizing gas when forming the atomizing mixture. For example, the amount of additive gas injected can be controlled to achieve one or more desired ranges of atomizing gas to additive gas ratios in the resulting atomizing mixture.

For reactive metal powders formed without the addition of additive gases, it was observed that reactive metal powders with various particle size distributions that had undergone the sieving and blending steps did not always flow sufficiently to allow measurement in a Hall flowmeter their flowability (see Figure 5 of ASTM B213). For example, according to ASTM B213, reactive metal powders falling within a particle size distribution between 10-53 μm do not flow in a Hall flowmeter.

Without being bound by theory, an important factor in the poor flowability of active metal powders is their susceptibility to static electricity. The sieving, blending and manipulation steps can cause particles of the active metal powder to collide with each other, thereby increasing the level of static electricity. This static electricity further creates cohesion between the particles, which results in poor flow of the active metal powder.

The original active metal powder formed by atomizing the heated metal source by contacting the heated metal source with the atomizing gas and the additive gas is further collected. The collected raw active metal powder contains a mixture of metal particles of various sizes. The raw active metal powder is further sieved to separate the raw active metal powder into different size distributions, eg 10-45 μm, 15-45 μm, 10-53 μm, 15-53 μm and/or 25-45 μm.

After sieving, each particle size distribution of the metal powder was stirred separately in distilled or demineralized water. Agitation can help remove static charges that build up on the surface of the metal powder particles.

After sieving, each particle size distribution of the metal powder was kept dry separately.

It was observed that the active metal powders formed according to the various exemplary atomization methods described herein, wherein the heated metal source was contacted with the additive gas, exhibited significantly higher fluidity. Flow between metal powders formed according to different methods can be sieved mostly in metal powders having a size distribution of 10-45 μm, 15-45 μm, 10-53 μm, 15-53 μm and/or 25-45 μm or similar particle size distribution sexual differences. It should be understood, however, that metal powders of other size distributions may also exhibit a slight increase in fluidity when formed according to a method comprising contacting a heated metal source with an additive gas.

It is known that titanium forms a native surface oxide layer upon exposure to air. This layer is typically about 3-5 nm and consists essentially of titanium oxide (S. Axelsson, 2012, p. 37). Natural oxides can act as passivation layers and reduce reactivity. This native layer has a strong affinity for water vapor (hydrophilic) and has hydroxyl groups on the surface (Tanaka et al., 2008, p. 1; Lu et al., 2000, p. 1).

Without being bound by theory, when the heated metal source is contacted with the additive gas during atomization, the atoms and/or molecules of the additive gas react with the particles of the active metal powder in forming these particles. Thus, a first layer formed of the heated metal and additive gas compound and depleted through the thickness is formed on the particle outer surface of the active metal particles. This layer is thicker and deeper in the surface and lies below the native oxide layer. For example, the heated metal and additive gas compound in the depletion layer is a metal oxide, nitride, carbide or halide. As the atoms of the additive gas are depleted through the thickness of the surface layer, it forms non-stoichiometric compounds with the metal. This compound imparts a substantially positive charge to the first layer.

This first layer can only be formed at high temperatures because the electronegative atoms and/or molecules need to have sufficient energy to diffuse into the surface layer more than in the native oxide layer.

A second layer as a natural oxide layer is further formed on the particle surfaces of the active metal powder. The hydroxyl groups formed at the surface give the second layer a substantially negative charge.

The first layer having a substantially positive charge and the second layer having a substantially negative charge together form an electric double layer. The combined charge of the bilayer has a substantially neutral charge (ie, the net charge tends to zero). This neutral charge on the surfaces of the active metal powder particles can help improve the flow properties of the active metal powders formed according to the exemplary methods and apparatus described herein. For example, while a net charge on a particle (eg, formed according to conventional atomization methods) will favor particle polarization and increase interaction with other particles, weakly charged particles will have little electrical interaction with other particles. This reduced interaction can result in excellent flow.

6 shows a schematic diagram of particles 100 of active metal powder formed according to an atomization process, wherein the heated metal source 16 is not in contact with the additive gas. The formed particles 100 generally include particle bodies 108 (eg, Ti-6Al-4V particles) and a surface native oxide layer 116 . The surface native oxide layer 116 has a generally negative charge, which results in a particle 100 formed with a net non-zero charge (ie, Q _net ≠ 0 for particle 108). This negative charge provides greater polarizability. Particles 108 also contain hydroxyl groups at surface 116 .

7 shows a schematic diagram of particles 140 of active metal powder formed according to an exemplary atomization method described herein, wherein heated metal source 16 is contacted with an additive gas. A first layer 148 (or layer 1 ) is formed on the outer surface of the particle body 156 (eg, Ti-6Al-4V particles). It results from the recombination of heated metal with electronegative atoms and/or molecules depleted through the thickness. A second layer 164 (or layer 2 ) as a native oxide layer is further formed on the surface of the particle body 156 . As described elsewhere herein, the first layer 148 and the second layer 164 have substantially neutral combined charges, resulting in particles 140 formed with substantially _net zero charge (Qnet≈0) and lower polarizability .

The amount of additive gas injected with the atomizing gas to form the atomized mixture can be controlled according to the theory that electronegative atoms and/or molecules from the additive gas become surface additives on the particles of the original metal powder formed. Because it varies quasi-linearly with the productivity of the metal powder with a predetermined particle size distribution. The amount of additive gas required to form layer 1 is related to the total surface area of the metal particles, which depends on the production rate and particle size distribution (see Figure 8). The concentration of the additive gas and the thermal conditions of the metal particles will determine the depth of the depletion layer of layer 1 .

Further based on the theory that electronegative atoms and/or molecules from the additive gas become surface additives on the particles of the original metal powder formed, the amount of additive gas injected with the atomizing gas to form the atomized mixture can be controlled. Because it varies with the total area of the metal powder particles formed as shown in FIG. 8 .

Further based on the theory that electronegative atoms and/or molecules from the additive gas become surface additives on the particles of the original metal powder formed, the amount of additive gas injected with the atomizing gas to form the atomized mixture can be controlled. Because it varies with the temperature of the surface of the original metal powder particles formed. The reaction rate of this chemical reaction with activation energy E generally follows an Arhenius relationship with temperature T:

Therefore, injecting the additive gas at high temperature is more efficient and requires less additive gas concentration to produce the desired depletion depth and form layer 1 .

FIG. 8 shows a schematic diagram of a particle 180 having a radius R and a depletion depth δ at the surface of the particle 188 . The total surface area of the particles is S ₁ =4πR ² .

它随着颗粒半径的减小而线性增加。FIG. 8 further shows a schematic diagram of a plurality of particles of the same size (n particles) 200 having the same total mass as the mass of particles 180 . Particles 200 are smaller in size than particles 180 but have a greater total surface area than particles 180, each particle 200 has a radius r and the total number of particles is n ^{= R3} /r3. The combined surface area of particle 200 is

It increases linearly with decreasing particle radius.

Therefore, the amount of surface additive added is a function of the total surface area, since the volume to be treated is the product of the total surface area and the depletion depth.

For example, the resulting metal powder may have less than about 100, 150, 200, 300, 500, 1000, or 1500 ppm of electronegative atoms and/or molecules (eg, electronegative atoms contained in the additive gas used to produce the powder) and/or molecular elements).

Experiment 1

Four different powders were produced by plasma atomization under the same experimental conditions, except for the composition in which the atomized mixture was contacted with a heated metal source.

The nebulizing gas was high purity argon (99.997%).

In Tests 1 and 2, only the atomizing gas was used to contact the heated metal source during the atomization process.

In Test 3, air was injected into high purity argon to form an 80 ppm atomized mixture of air and argon. The heated metal is contacted with the atomized mixture during atomization.

In Test 4, _O2 was injected into high purity argon to form a 50 ppm _O2 and argon atomized mixture. The heated metal is contacted with the second atomized mixture during atomization.

After contact with the atomizing gas (tests 1 and 2) or the atomizing mixture (tests 3 and 4), the resulting pristine reactive metal powders were sieved to separate the 15-45 μm particle size distribution.

The sieved powders are then blended to ensure uniformity.

The powder is further stirred in distilled or demineralized water to remove the electrostatic charge accumulated during the previous steps.

The powder was dried in air at 80°C for 12 hours.

Figure 9 is a graph illustrating a comparison of oxygen distribution between different samples by TOF-SIMS. For tests 1 to 4, TOF-SIMS characterization of the powders was obtained. The presence of depletion layers can be associated with high flow powders, as shown in Table 1.

The TOF-SIMS characteristics of the treated fine powder can be clearly seen from Figure 9. The tail of oxygen content goes deeper in the surface layer. It is crucial to obtain a depletion layer with a certain critical depth in order to obtain improved flow behavior. TOF-SIMS results indicate that the depletion layer has a depth of about 100 nm. Depth can be estimated by calibrating the sputtering rate of the ion beam obtained on the Ti-6Al-4V body part with a profiler. The sputtering rate depends on the ion beam intensity and material type. Calibration is done before measurement and the ion beam energy is very stable.

Table 1: Description of Tests 1-4 with Flowability and Apparent Density Measured on 15-45 μm Particle Size Distribution

Table 2: Powder chemical composition of tests 1-4 on 15-45 μm particle size distribution

Table 3: Particle size distribution for tests 1-4 on 15-45 μm particle size distribution

Statistical analysis of many batches determined that air injection (Test 3) added about 100-150 ppm nitrogen and about 50 ppm oxygen to the powder. Injecting air improves the flowability of the formed active metal powder.

It was further determined from statistical data analysis that only _O2 injection (Test 4) added about 150-200 ppm of oxygen and no nitrogen.

Additional successful tests for flowability of the 15-45 μm particle size distribution were carried out by injecting water vapour. An improvement in flowability was also observed for the 15-45 μm particle size distribution.

The treatment carried out maintained a satisfactory chemical composition according to the composition of the standards ASTM B348, ASTM F2924 and ASTM F3001. If the feedstock will be slightly higher in oxygen, it will also meet the requirements of AMS 4998.

Figure 10 is a photograph of a batch of about 100 kg of metal powder formed according to an atomization process that did not include contact with additive gases. Due to aggregates, 90% of the collection bucket was filled and had poor visual compaction.

Figure 11 is a photograph of a batch of about 100 kg of metal powder formed according to an atomization process in which a metal source is in contact with an additive gas. Due to improved flow and lower surface interaction between particles, 20% of the collection bucket was filled with the same amount of material used during the run of Figure 10 and visually compacted well.

Tests similar to Tests 3 and 4 were carried out by injecting additive gas intermittently. The treatment was found to still be effective, while having the advantage of adding less impurities to the final product.

Similarly, we have found that mixtures of up to 30% powder with good flow can be blended with 70% powder that does not flow in the Hall meter, and the resulting powder still flows, if not as well as the starting powder.

Experiment 2

Post heat treatment is performed on the metal powder that has been formed by a process that does not use additive gases.

More specifically, the formed metal powder was heated at about 250°C for 12 hours in an air atmosphere. This heating is expected to result in the addition of oxygen to the surface of the pristine metal powder particles and increase the thickness of the native oxide layer.

It was observed that a posteriori oxidation/nitridation did not produce similar results for contact with additive gases in the atomization zone of the atomization process. No improvement in the fluidity of the metal powder was observed.

It appears that a posteriori heating of the metal powder that has formed will only thicken the native oxide layer and not have the ability to provide sufficient depth and depletion of the oxide/nitride layer on the particles. Thicker oxide layers will also remain quasi-stoichiometric and fail to provide the positively charged layer 1 provided by the depletion layer.

Without being bound by theory, the high temperatures involved and the low concentration of additive gas during atomization enable the formation of an oxidation/nitridation reaction that depletes the oxide/nitride layer when the metal source is in contact with the additive gas.

The embodiments of paragraphs [18] to [195] of the present disclosure are presented in this disclosure in such a way as to demonstrate that each combination of embodiments is possible where applicable. Accordingly, these embodiments are presented in the specification in a manner equivalent to making dependent claims for all embodiments dependent on any preceding claim (covering previously presented embodiments), thereby demonstrating that they may be possible in all possible ways combine it all toghther. For example, where applicable, all possible combinations between the embodiments of paragraphs [18] to [195] and the processes of paragraphs [7] to [15] are covered herein by this disclosure.

It will be understood that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements or steps. Furthermore, numerous specific details are set forth in order to provide a thorough understanding of the exemplary embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein may be practiced without these specific details. In other instances, well-known methods, procedures, and components have not been described in detail so as not to obscure the embodiments described herein. Furthermore, this description should not be viewed in any way as limiting the scope of the embodiments described herein, but merely as describing implementations of the various embodiments described herein.

Claims (99)

1. An active metal powder in-flight heat treatment process, comprising: provide reactive metal powders; and During the in-flight heat treatment process, the active metal powder is contacted with at least one additive gas, thereby obtaining a pristine active metal powder, the pristine active metal powder comprising: Particle size distribution from 10 to 53 μm with flowability of less than 40 seconds measured according to ASTM B213; and / or Particle size distribution from 45 to 180 μm with flowability of less than 28 seconds measured according to ASTM B213; wherein the original active metal powder has an added content of various electronegative atoms and/or molecules from the additive gas of less than 1000 ppm; wherein the active metal powder is contacted with at least one additive gas to form a first layer on the outer surfaces of the particles of the active metal powder, the first layer comprising atoms of the active metal powder and atoms of the additive gas and and/or molecules, and a second layer is further formed on the first layer, the second layer is a native oxide layer, and the first layer is a depletion layer with a depth and thickness greater than that of the second layer. 2. An active metal powder in-flight heat treatment process, comprising: provide reactive metal powders; and During the in-flight heat treatment process, the active metal powder is contacted with at least one additive gas, thereby obtaining a pristine active metal powder, the pristine active metal powder comprising: Particle size distribution from 10 to 53 μm with flowability of less than 30 seconds measured according to ASTM B213; wherein the original active metal powder has an added content of various electronegative atoms and/or molecules from the additive gas of less than 1000 ppm; wherein the active metal powder is contacted with at least one additive gas to form a first layer on the outer surfaces of the particles of the active metal powder, the first layer comprising atoms of the active metal powder and atoms of the additive gas and and/or molecules, and a second layer is further formed on the first layer, the second layer is a native oxide layer, and the first layer is a depletion layer with a depth and thickness greater than that of the second layer. 3. An active metal powder in-flight heat treatment process, comprising: Provide active metal powder; mixing together an in-flight thermal treatment process gas and at least one additive gas to obtain an in-flight thermal treatment process gas mixture; During the in-flight heat treatment process, the active metal powder is brought into contact with the mixture, thereby obtaining a pristine active metal powder, the pristine active metal powder comprising: Particle size distribution from 10 to 53 μm with flowability of less than 40 seconds measured according to ASTM B213; and / or Particle size distribution from 45 to 180 μm with flowability of less than 28 seconds measured according to ASTM B213; wherein the original active metal powder has an added content of various electronegative atoms and/or molecules from the additive gas of less than 1000 ppm; wherein the active metal powder is contacted with at least one additive gas to form a first layer on the outer surfaces of the particles of the active metal powder, the first layer comprising atoms of the active metal powder and atoms of the additive gas and and/or molecules, and a second layer is further formed on the first layer, the second layer is a native oxide layer, and the first layer is a depletion layer with a depth and thickness greater than that of the second layer. 4. An active metal powder in-flight heat treatment process, comprising: Provide active metal powder; mixing together an in-flight thermal treatment process gas and at least one additive gas to obtain an in-flight thermal treatment process gas mixture; During the in-flight heat treatment process, the active metal powder is brought into contact with the mixture, thereby obtaining a pristine active metal powder, the pristine active metal powder comprising: Particle size distribution from 10 to 53 μm with flowability of less than 30 seconds measured according to ASTM B213; wherein the original active metal powder has an added content of various electronegative atoms and/or molecules from the additive gas of less than 1000 ppm; wherein the active metal powder is contacted with at least one additive gas to form a first layer on the outer surfaces of the particles of the active metal powder, the first layer comprising atoms of the active metal powder and atoms of the additive gas and and/or molecules, and a second layer is further formed on the first layer, the second layer is a native oxide layer, and the first layer is a depletion layer with a depth and thickness greater than that of the second layer. 5. An active metal powder in-flight heat treatment process, comprising: Provide active metal powder; mixing together an in-flight thermal treatment process gas and at least one additive gas to obtain an in-flight thermal treatment process gas mixture; During the in-flight heat treatment process, contacting the active metal powder with the in-flight heat treatment process gas mixture to obtain pristine metal powder; sieving the raw reactive metal powder to obtain a powder having a predetermined particle size; and contacting the powder having the predetermined particle size with water; wherein the original active metal powder has an added content of various electronegative atoms and/or molecules from the additive gas of less than 1000 ppm; wherein the active metal powder is contacted with at least one additive gas to form a first layer on the outer surfaces of the particles of the active metal powder, the first layer comprising atoms of the active metal powder and atoms of the additive gas and and/or molecules, and a second layer is further formed on the first layer, the second layer is a native oxide layer, and the first layer is a depletion layer with a depth and thickness greater than that of the second layer. 6. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 10 to 45 μιη with a flowability of less than 40 seconds as measured according to ASTM B213. 7. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 15 to 45 [mu]m having a flowability of less than 40 seconds as measured according to ASTM B213. 8. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 15 to 53 μιη with a flowability of less than 40 seconds as measured according to ASTM B213. 9. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 25 to 45 [mu]m having a flowability of less than 40 seconds as measured according to ASTM B213. 10. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 25 to 53 [mu]m with a flowability of less than 40 seconds as measured according to ASTM B213. 11. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 75 μm having a flowability of less than 28 seconds as measured according to ASTM B213. 12. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 106 [mu]m having a flowability of less than 28 seconds as measured according to ASTM B213. 13. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 150 [mu]m having a flowability of less than 28 seconds as measured according to ASTM B213. 14. The process of claim 2 or 4, wherein the virgin reactive metal powder comprises a particle size distribution of 10 to 45 [mu]m having a flowability of less than 30 seconds as measured according to ASTM B213. 15. The process of claim 2 or 4, wherein the virgin reactive metal powder comprises a particle size distribution of 15 to 45 [mu]m with a flowability of less than 30 seconds as measured according to ASTM B213. 16. The process of claim 2 or 4, wherein the virgin reactive metal powder comprises a particle size distribution of 15 to 53 [mu]m with a flowability of less than 30 seconds as measured according to ASTM B213. 17. The process of claim 2 or 4, wherein the virgin reactive metal powder comprises a particle size distribution of 25 to 45 [mu]m with a flowability of less than 30 seconds as measured according to ASTM B213. 18. The process of claim 2 or 4, wherein the virgin reactive metal powder comprises a particle size distribution of 25 to 53 [mu]m having a flowability of less than 30 seconds as measured according to ASTM B213. 19. The process of any of claims 1-5, wherein the at least one additive gas is an oxygen-containing gas. 20. The process of any of claims 1-5, wherein the at least one additive gas comprises an oxygen-containing gas. 21. The process of any of claims 1-5, wherein the at least one additive gas comprises an oxygen-containing gas and an inert gas. 22. The process of claim 21, wherein the inert gas is argon. 23. The process of any of claims 1-5, wherein the at least one additive gas comprises air. 24. The process of any of claims 1-5, wherein the at least one additive gas is a halogen-containing gas. 25. The process of claim 24, wherein the halogen is F, Cl, Br or I. 26. The process of any of claims 1-5, wherein the at least one additive gas is a hydrogen-containing gas. 27. The process of any of claims 1-5, wherein the at least one additive gas is a sulfur-containing gas. 28. The process of any of claims 1-5, wherein the at least one additive gas is a nitrogen-containing gas. 29. The process of any one of claims 1-5, wherein the at least one additive gas is selected from the group consisting of _O2 , _H2O , _CO , _CO2 , NO2, _N2 , _NO3 , Cl ₂ , SO ₂ , SO ₃ and mixtures thereof. 30. The process of any one of claims 1-5, wherein the active metal powder is comprised of at least one selected from the group consisting of titanium, titanium alloys, zirconium, zirconium alloys, magnesium, magnesium alloys, aluminum, and aluminum alloys A type of metal powder. 31. The process of claim 30, wherein the active metal powder comprises at least one of titanium, zirconium, magnesium, and aluminum. 32. The process of claim 30, wherein the active metal powder comprises titanium. 33. The process of claim 30, wherein the active metal powder comprises a titanium alloy. 34. The process of claim 30, wherein the reactive metal powder comprises zirconium. 35. The process of claim 30, wherein the active metal powder comprises a zirconium alloy. 36. The process of claim 30, wherein the active metal powder is a metal powder comprising at least one member selected from one of titanium and titanium alloys. 37. The process of any of claims 1-5, wherein the process is carried out by means of at least one plasma torch. 38. The process of claim 37, wherein the at least one plasma torch is a radio frequency (RF) plasma torch. 39. The process of claim 37, wherein the at least one plasma torch is a direct current (DC) plasma torch. 40. The process of claim 37, wherein the at least one plasma torch is a microwave (MW) plasma torch. 41. A process for preparing a mixture of active metal powders comprising combining an active metal powder obtained by a process as defined in any one of claims 1-40 with a process as defined in any one of claims 1-38 The active metal powders obtained are mixed together, wherein the process for obtaining the active metal powder by a process as defined in any one of claims 1-40 and the process for obtaining active metal powder by a process as defined in any one of claims 1-38 process is different. 42. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 10 to 53 [mu]m having a flowability of less than 36 seconds as measured according to ASTM B213. 43. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 10 to 53 μιη having a flowability of less than 32 seconds as measured according to ASTM B213. 44. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 10 to 53 [mu]m having a flowability of less than 30 seconds as measured according to ASTM B213. 45. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 10 to 53 [mu]m having a flowability of less than 28 seconds as measured according to ASTM B213. 46. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 10 to 45 [mu]m having a flowability of less than 36 seconds as measured according to ASTM B213. 47. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 10 to 45 μιη having a flowability of less than 32 seconds as measured according to ASTM B213. 48. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 10 to 45 [mu]m having a flowability of less than 30 seconds as measured according to ASTM B213. 49. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 10 to 45 [mu]m having a flowability of less than 28 seconds as measured according to ASTM B213. 50. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 15 to 45 [mu]m having a flowability of less than 36 seconds as measured according to ASTM B213. 51. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 15 to 45 μιη with a flowability of less than 32 seconds as measured according to ASTM B213. 52. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 15 to 45 [mu]m having a flowability of less than 30 seconds as measured according to ASTM B213. 53. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 15 to 45 μιη having a flowability of less than 28 seconds as measured according to ASTM B213. 54. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 15 to 53 μιη having a flowability of less than 36 seconds as measured according to ASTM B213. 55. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 15 to 53 μιη having a flowability of less than 32 seconds as measured according to ASTM B213. 56. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 15 to 53 [mu]m having a flowability of less than 30 seconds as measured according to ASTM B213. 57. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 15 to 53 μιη having a flowability of less than 28 seconds as measured according to ASTM B213. 58. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 25 to 45 μιη having a flowability of less than 36 seconds as measured according to ASTM B213. 59. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 25 to 45 μιη having a flowability of less than 32 seconds as measured according to ASTM B213. 60. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 25 to 45 [mu]m having a flowability of less than 30 seconds as measured according to ASTM B213. 61. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 25 to 45 μιη having a flowability of less than 25 seconds as measured according to ASTM B213. 62. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 25 to 53 μιη having a flowability of less than 36 seconds as measured according to ASTM B213. 63. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 25 to 53 μιη having a flowability of less than 32 seconds as measured according to ASTM B213. 64. The process of claim 1 or 3, wherein the virgin reactive metal powder comprises a particle size distribution of 25 to 53 μιη having a flowability of less than 30 seconds as measured according to ASTM B213. 65. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 25 to 53 μιη having a flowability of less than 25 seconds as measured according to ASTM B213. 66. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 75 μιη having a flowability of less than 26 seconds as measured according to ASTM B213. 67. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 75 μm having a flowability of less than 25 seconds as measured according to ASTM B213. 68. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 75 μιη having a flowability of less than 24 seconds as measured according to ASTM B213. 69. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 75 μm having a flowability of less than 23 seconds as measured according to ASTM B213. 70. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 106 [mu]m having a flowability of less than 26 seconds as measured according to ASTM B213. 71. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 106 [mu]m having a flowability of less than 25 seconds as measured according to ASTM B213. 72. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 106 [mu]m having a flowability of less than 24 seconds as measured according to ASTM B213. 73. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 106 μιη having a flowability of less than 23 seconds as measured according to ASTM B213. 74. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 150 [mu]m having a flowability of less than 26 seconds as measured according to ASTM B213. 75. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 150 μm having a flowability of less than 25 seconds as measured according to ASTM B213. 76. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 150 μm having a flowability of less than 24 seconds as measured according to ASTM B213. 77. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 150 μιη having a flowability of less than 23 seconds as measured according to ASTM B213. 78. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 180 μιη having a flowability of less than 26 seconds as measured according to ASTM B213. 79. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 180 μιη having a flowability of less than 25 seconds as measured according to ASTM B213. 80. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 180 μιη having a flowability of less than 24 seconds as measured according to ASTM B213. 81. The process of any one of claims 1-5, wherein the virgin reactive metal powder comprises a particle size distribution of 45 to 180 μιη having a flowability of less than 23 seconds as measured according to ASTM B213. 82. The process of any one of claims 1-5, wherein the first layer has a substantially positive charge and the second layer has a substantially negative charge, and wherein the first layer and the second layer have a substantially neutral combined charge. 83. The process of any one of claims 1-4, further comprising: The raw active metal powder is sieved to separate the raw active metal powder by particle size distribution. 84. The process of claim 83, further comprising: After sieving, the separated raw material powders were stirred separately in water. 85. The process of claim 84, wherein the water is distilled or demineralized water. 86. The process of claim 84 or 85, wherein the flowability of the reactive metal powder is measured on dry sieved metal powder after having been agitated. 87. The process of any one of claims 1-5, wherein the active metal powder has an added content of electronegative atoms from an additive gas of less than 1000 ppm. 88. The process of any one of claims 1-5, wherein the active metal powder has an added content of electronegative atoms from an additive gas of less than 500 ppm. 89. The process of any one of claims 1-5, wherein the active metal powder has an added content of electronegative atoms from an additive gas of less than 250 ppm. 90. The process of any one of claims 1-5, wherein the active metal powder has an added content of electronegative atoms from an additive gas of less than 200 ppm. 91. The process of any one of claims 1-5, wherein the active metal powder has an added content of electronegative atoms from an additive gas of less than 150 ppm. 92. The process of any one of claims 1-5, wherein the active metal powder has an added content of electronegative atoms from an additive gas of less than 100 ppm. 93. The process of any one of claims 1-5, wherein the reactive metal powder has an added content of each of the electronegative atoms and/or molecules from an additive gas of less than 500 ppm. 94. The process of any one of claims 1-5, wherein the reactive metal powder has an added content of each of the electronegative atoms and/or molecules from an additive gas of less than 250 ppm. 95. The process of any one of claims 1-5, wherein the reactive metal powder has an added content of each of the electronegative atoms and/or molecules from an additive gas of less than 200 ppm. 96. The process of any one of claims 1-5, wherein the reactive metal powder has an added content of each of the electronegative atoms and/or molecules from an additive gas of less than 150 ppm. 97. The process of any one of claims 1-5, wherein the reactive metal powder has an added content of each of the electronegative atoms and/or molecules from an additive gas of less than 100 ppm. 98. The process of any of claims 3-5, wherein the thermal treatment process gas is an inert gas and the at least one additive gas is an oxygen-containing gas. 99. The process of claim 98, wherein the inert gas is selected from the group consisting of argon, helium, or mixtures thereof.

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